I want to invest in PPF. Can anyone give me details about it? Can I open PPF in banks or I have to do it in post office only. Can I open my PPF a/c in bank of Maharashtra? Can I change the amount in any year? E.g. suppose I opt for 15 year PPF and want to start PPF by rs.200 p.m. Then can i change it to Rs. 400 p.m. In second year onwards. in short can I change deposit amount at any time?